The Halona Blow-hole located on the island of Oahu off of Hanauma Bay is a rock formation and a blow-hole formed by underwater lava which took the form of a tube and has an opening on both sides of it. As the ocean water enters the tube, the pressure increases as the tube narrows such that the water shoots upward into the air sometimes to a high of 30 feet or more. The Halona Blow-hole is a popular attraction. The location is very scenic, there are steep cliffs and fantastic views.

The blow-hole is most active during high tide. It is also the best location to go and look out for humpback whales or Honu (the Hawaiian green turtle). When there is no surf and a light northerly wind blowing, diving is possible along the coast. If the waves are breaking, it is recommended to dive elsewhere. The tidal change produces very strong currents known as 'Molokai Express" that can drag a person out to sea. Some persons have lost their life trying to sit on the blow-hole or trying to hold parts of their body into the stream of water. The area is quite dangerous, so it is best to be careful and stay at the lookout point and enjoy the view from a safe distance.

The Hawaiian name Halona means "peering place". On a very nice day, the view can be very fantastic. From far off on the horizon, the islands of Molokai, Maui and Lanai can be seen. To the right of the blow-hole is located Halona Cove, a small sandy beach that is perfect for swimming when the surf is calm. The site is also known for the famous love scene of Burt Lancaster and Deborah Kerr in the film "From here to eternity".